Time Varying Static Loads

Define a dynamic load case by multiplying static load cases already entered by time functions, which should be defined as a Normal type in the "Time Forcing Functions".

This function is used to reflect the effect of the self-weight in the time history analysis due to seismic loads.

First, define the self-weight using a Time Forcing Function and then assign the Time History Load Case for the self-weight. Next, define a Time History Load Case for the seismic load, selecting the previously defined self-weight time history load case as Subsequent to Load Case" under Order in Sequential Loading" Then perform analysis. This will ensure that when performing seismic analysis considering the self-weight; the self-weight is applied first, and then the seismic load is applied to the structure while maintaining the effect of the self-weight.   

From the Main Menu select Load > Seismic > Time History Analysis Data > Time Varying Static Loads.

Time History Load Case Name

Select a time history analysis load case entered in "Time History Load Cases". Click to define the relevant function if the load case has not been previously defined.

Static Load

Select a static load case to be used as a dynamic load case.

Function

Use the time history functions to multiply the static load cases and create a dynamic load case.

The values of the functions are unit-less. The type must be "Normal"

Function Name: Select the time history function defined in "Time Forcing Function".

Arrival Time: "Delay" time for the time load function. Enter the delay time when the time varying static load is applied some time after the time history analysis is initiated.

Scale Factor: Scale factor for the time load function. This Scale Factor is independent of the Scale Factor which is entered in the Time Forcing Function. You should exercise caution that the Scale Factors are not duplicated. Duplicating the input will multiply the Scale Factors.

Options

Add: To add to previously entered time forcing functions at specific nodes.

Replace: To replace previously entered time forcing functions at specific nodes.

Delete: To delete previously entered time forcing functions at specific nodes.